JP2019535154A - Beam selection method and apparatus - Google Patents

Abstract

The present application provides a beam selection method. This method includes a step a for presetting a beam from the first level to the K level and a correspondence relationship between the beams at each level, and a step b for transmitting each beam at the first level to a user terminal (UE). Receiving a beam index fed back from the UE, and determining a beam corresponding to the received beam index, and corresponding to the determined beam if the determined beam is not the K-th level beam. Transmit each beam of the next level beam to the UE and return to step c, and if the determined beam is a Kth level beam, make the determined beam a candidate beam selected by the UE d And including. According to the present application, it is possible to reduce the overhead of beam selection and improve the accuracy of beam selection.

Description

  The present application relates to mobile communication technology, and in particular, to a beam selection method and apparatus.

  Currently, fourth generation mobile communication technology (4G) is beginning to be widely deployed in various parts of the world, but fifth generation mobile communication technology (5G) is an emerging research field. The application of large-scale multiple-input multiple-output (MIMO) has become a popular field of 5G technology. Compared to the conventional MIMO technology, large-scale MIMO can use more antennas for the base station (eNB), and provides a larger throughput. Further, by applying the beam forming technology under the large-scale MIMO technology, more accurate directivity service can be realized, so that more communication links can be provided in the same space. Such spatial multiplexing further improves the service capacity of the base station.

  As described above, it is possible to obtain more antennas and more beams by combining the large-scale MIMO technology and the beam forming technology. For example, in a 5G system, the number of usable beams can reach 512 and thus more. As the number of antennas, and the number and accuracy of beams increases, the capacity of the system can be greatly improved. Also, as the number of beams increases, the width of each beam also becomes narrower, so a more accurate directivity service can be realized. In this case, how to select a beam by the mobile terminal (UE) is one of the problems to be solved in the 5G communication system.

  As explained above, when applying a large-scale MIMO technique, the number and accuracy of beams that can be generated are greatly increased. If all the beams are transmitted to the UE one by one by the exhaustive method, and the UE performs measurement one by one and makes a selection from among them, a very large signaling overhead occurs. For this reason, in the embodiment of the present application, a beam selection method is provided that avoids an excessively large signaling overhead in the beam selection process by performing beam selection in a manner that hierarchically selects beams.

  In an embodiment of the present application, a beam selection method is provided. In this method, a step a in which correspondences between beams from the first level to the Kth level (K is a natural number) and beams at each level are set in advance, and each beam at the first level is set to a user terminal (UE). And b receiving the beam index fed back from the UE, determining a beam corresponding to the received beam index, and determining if the determined beam is not the K-th level beam. Each beam of the next level beam corresponding to the received beam is transmitted to the UE, and returning to step c, if the determined beam is the Kth level beam, the determined beam is selected as a candidate selected by the UE. A beam d.

  In the embodiment of the present application, a base station for realizing the beam selection method is also provided. The base station includes a processor and a storage connected to the processor, wherein the storage stores a machine-readable command module executable by the processor, and the machine-readable command module stores a beam selection setting. And transmitting a beam reference signal to the user terminal (UE), a setting module for determining the beam of each level from the first level to the Kth level (K is a natural number) and the correspondence between the beams of each level. A beam reference signal transmission module, a feedback reception module for receiving a beam index fed back from the UE, and a beam reference signal transmission module to transmit the beam reference signal of the first level beam set by the setting module to the UE. The beam index fed back from the UE. Is received by the feedback receiving module, a beam corresponding to the beam index fed back from the UE is determined, and it is determined whether the beam is a K-th level beam. If it is a beam, the beam is a beam selected by the UE, and if the beam is not a Kth level beam, a beam reference signal of the next level beam corresponding to the beam is transmitted to the UE. And a control module for controlling the beam reference signal transmission module.

  In an embodiment of the present application, a non-volatile computer readable storage medium is also provided. A machine-readable command is stored in the storage medium, and the machine-readable command sets the beam from the first level to the K-th level (K is a natural number) and the correspondence relationship between the beams at each level; Transmitting each beam of the first level to a user equipment (UE); b receiving a beam index fed back from the UE; and determining a beam corresponding to the received beam index If the beam is not a Kth level beam, send each beam of the next level beam corresponding to the determined beam to the UE, return to step c, and if the determined beam is the Kth level beam Step d can be performed by the processor to complete the determined beam with the determined beam as the candidate beam selected by the UE.

  According to the beam selection method in the present application, it is not necessary to cause the UE to transmit and measure candidate beams one by one, and the overhead of the beam selection process can be greatly reduced when there are many candidate beams. Also, in the beam selection method in the present application, since the upper level beam width is required to be larger than the lower level beam width, the UE first selects from the wide beams. Select from narrow beams. Thereby, it is possible to better resist the influence of the phase noise on the accuracy of beam selection, improve the accuracy of beam selection, and further guarantee the communication quality.

In order to more clearly explain the configuration of the present application, the drawings necessary for the description of the embodiments will be briefly introduced below. As will be apparent, the drawings in the following description are only a few examples of the present application. For those skilled in the art, other drawings can be obtained based on these drawings on the premise of not performing creative labor.
The example of the beam of each level in one Example of this application is shown. The flowchart of the beam selection method in one Example of this application is shown. The process of beam selection by a base station and a single UE is shown. A process in which a base station and a plurality of UEs perform beam selection is shown. The flowchart of the beam selection method in the other Example of this application is shown. An example in which fine phase adjustment is performed on a selected beam in an embodiment of the present application will be described. 6 shows a flowchart of a method for fine phase adjustment of a selected beam in an example of the present application. The example which performs fine adjustment of a phase with respect to the selected beam in the other Example of this application is shown. The example which performs fine adjustment of a phase with respect to the selected beam in the other Example of this application is shown. It is a schematic diagram of the internal structure of the base station in one Example of this application. It is a schematic diagram of the other internal structure of the base station in the Example of this application.

  Hereinafter, the configuration of the present application will be described clearly and completely with reference to the drawings. Apparently, the described embodiments are some embodiments of the present application and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained on the assumption that those skilled in the art do not perform creative labor belong to the protection scope of the present application.

  As described above, it is possible to obtain more antennas and more beams by combining the large-scale MIMO technology and the beam forming technology. For example, in a 5G system, the number of usable beams can reach 512 and thus more. As the number of antennas, and the number and accuracy of beams increases, the capacity of the system can be greatly improved. Also, as the number of beams increases, the width of each beam also becomes narrower, so a more accurate directivity service can be realized. In this case, how to select a beam by the mobile terminal (UE) is one of the problems to be solved in the 5G communication system.

  As explained above, when applying a large-scale MIMO technique, the number and accuracy of beams that can be generated are greatly increased. If all the beams are transmitted to the UE one by one by the exhaustive method, and the UE performs measurement one by one and makes a selection from among them, a very large signaling overhead occurs. For this reason, in the embodiment of the present application, a beam selection method is provided that avoids an excessively large signaling overhead in the beam selection process by performing beam selection in a manner that hierarchically selects beams.

  In the embodiment of the present invention, before performing beam selection, it is first necessary to make basic settings for beam selection. These settings mainly include the following points.

  1. The number N of candidate beams to be selected is determined. In the embodiment of the present invention, a beam generated by the base station and selectable by the UE is referred to as a candidate beam. The number of candidate beams may be related to the number of transmission antennas of the base station. When the arrangement of the base station is completed, generally, the number N of beams that can be generated by the base station is determined. Of course, the number of candidate beams may be determined by system settings.

  2. Determine the number of levels K of the hierarchical beam selection method. The number K of hierarchical beam selection levels may be a constant value based on experience. For example, in consideration of the complexity of the hierarchical beam selection method, the number of beam selection levels K = 3 is set directly at the time of system setting. The number K of beam selection levels may be determined according to specific usage scenarios and needs. For example, for a system with a high delay requirement, the number of beam selection levels K may be reduced in order to reduce the delay.

3. Based on the N candidate beams and the number K of beam selection levels, a beam included in each level is determined among the beams from the first level to the Kth level. In the embodiment of the present application, the beam from the first level to the Kth level needs to satisfy the following requirements.
1) Each beam at the i-th level corresponds to two or more beams at the (i + 1) -th level. Here, i = [1, K−1].
2) Any of the i + 1th level beams corresponds to one beam of the ith level.
3) The width of the i-th level beam is larger than the width of the i + 1-th level beam.
4) The N candidate beams are included in the K-th level beam.
5) The direction of each beam at the i-th level correlates with the direction of two or more beams at the (i + 1) -th level corresponding to the beam. Specifically, the correlation coefficient between the coefficient of a beam having an i-th level and the coefficients of two or more beams of the (i + 1) -th level corresponding to the beam may be expressed as being greater than a preset threshold value. good. That is, when the correlation coefficient of the coefficients of the two beams is larger than a preset threshold, the two beams are considered to be correlated, and the correlation coefficient of the coefficients of the two beams is less than or equal to the preset threshold. In some cases, the two beams are considered uncorrelated. Specifically, the beam coefficient may be an array factor of the beam.

  The beams from the first level to the Kth level may satisfy the following requirements. That is, the width of the i-th level beam is larger than the width of the i + 1-th level beam.

FIG. 1 shows an example of each determined level of beam. In this example, there are eight candidate beams and the number of beam selection levels is three. As shown in FIG. 1, in this example, the first level beam (Level 1) has two beams B ₁ and B ₂ , and each beam is a second level beam (Level 2). It corresponds to two of the four beams. For example, beams _{B 1} corresponds to the beam _{B 11} and _{B 12,} the beam _{B 2} corresponds to the beam _{B 21} and _{B 22.} Each of the four beams of the second level corresponds to two of the eight beams that are the third level beams (Level 3). For example, beam _{B 11} corresponds to the beam _{B 111} and _{B 112,} the beam _{B 12} corresponds to the beam _{B 121} and _{B 122,} beam _{B 21} corresponds to the beam _{B 211} and _{B 212,} beam _{B 22} Corresponds to beams B ₂₂₁ and B ₂₂₂ . The third level is eight candidate beams B ₁₁₁ , B ₁₁₂ , B ₁₂₁ , B ₁₂₂ , B ₂₁₁ , B ₂₁₂ , B ₂₂₁ , and B ₂₂₂ . As can be seen from FIG. 1, the widths of the two beams at the first level are each larger than the widths of the four beams at the second level, but the widths of the four beams at the second level are respectively at the third level. Greater than the width of the eight beams. Further, the directions of the beam B ₁ and the beams B ₁₁ and B ₁₂ are correlated, the directions of the beam B ₂ and the beams B ₂₁ and B ₂₂ are correlated, and the beam B ₁₁ and the beams B ₁₁₁ and B ₁₁₂ are correlated. The directions of the beam B ₁₂ and the beams B ₁₂₁ and B ₁₂₂ are correlated, the directions of the beam B ₂₁ and the beams B ₂₁₁ and B ₂₁₂ are correlated, and the beam B ₂₂ and the beam B ₂₂₁ are correlated. And the direction of B ₂₂₂ are correlated.

  When the above setting is completed, the beam selection can be started. FIG. 2 shows a beam selection method in the embodiment of the present application. As shown in FIG. 2, the method includes the following steps.

In step 201, the base station transmits each first level beam to the UE.
In the embodiment of the present application, what is transmitted from the base station to the UE in the beam selection process is a reference signal of each beam, and is abbreviated as a beam reference signal (BRS).

  In order to transmit the BRS to the UE, the base station performs related resource settings in advance, i.e., the substation uses which subframe or time instance, and the time instance. It is necessary to tell the UE which time frequency resource is used to transmit the BRS. In this embodiment, the above setting may be called BRS resource setting. In general, the base station may perform BRS resource setting by RRC control signaling or dynamic control signaling, or may pre-define BRS resources in RRC and then trigger by dynamic signaling. It may be set in advance so that BRS is included in either the frame or each time instance.

  In the normal case, the base station needs to instruct the UE in which subframe or time instance the base station performs BRS transmission. For example, the BRS instruction bit BRS_ENABLE may be added to the downlink control information (DCI) related to downlink transmission transmitted on the downlink control channel. Here, when BRS_ENABLE = 1, it indicates that the base station starts transmission of BRS. When the UE detects that the BRS instruction bit BRS_ENABLE is 1, the UE performs beam detection.

  In step 202, the UE performs beam detection, searches for a beam having the best reception performance, selects the beam, and feeds back the beam index (BI) of the selected beam to the base station.

  In order for the UE to feed back the beam index of the selected beam to the base station, the base station defines in advance the UE feedback mode and related settings, i.e., in which feedback mode the feedback is performed. It is necessary to tell to. In this embodiment, the feedback mode includes 1) a mode that does not require feedback, 2) a mode that feeds back only the beam index of the selected beam, and 3) a channel index in addition to the beam index of the selected beam. A quality indicator (CQI: Channel Quality Indicator), a rank indication (RI), a precoding matrix indicator (PMI: Precoding Matrix Indicator), and other modes that need to be fed back may also be included.

  In a normal case, it is necessary to add a feedback mode indication bit to instruct the UE in which feedback mode to perform feedback. For example, a feedback mode instruction bit FEEDBACK_MODE is added to DCI related to downlink transmission transmitted on the downlink control channel. Here, when FEEDBACK_MODE = 0, it is indicated that there is no need for feedback, and when FEEDBACK_MODE = 1, it is indicated that the UE only needs to feed back the beam index of the selected beam, and FEEDBACK_MODE = 2. In this case, it is indicated that the UE needs to feed back not only the beam index of the selected beam but also the parameters such as the current CQI, RI, and PMI. In this case, the UE performs feedback according to the instruction of the feedback mode instruction bit. For example, when the UE detects FEEDBACK_MODE = 1, it feeds back only the beam index of the selected beam. When the UE detects FEEDBACK_MODE = 2, the UE feeds back the beam index, CQI, RI, and PMI of the selected beam.

Regarding the timing when the UE performs feedback, in the long-term evolution system (LTE), a minimum interval between the transmission of the reference signal (RS) and the feedback of the channel state indicator (CSI) is defined. For this reason, in the Example of this invention, UE may determine the timing which performs feedback with the following two types of systems.
(1) The feedback timing is determined by the transmission time of the reference signal. For example, when the reference signal is received at time X, the UE performs feedback at time X + N.
(2) The timing of feedback is determined by a CSI feedback trigger (Trigger). For example, when receiving the CSI feedback trigger signal, the UE performs feedback.

  In step 203, the base station receives the beam index fed back from the UE and determines a beam corresponding to the received beam index.

  In this step, the base station may directly determine the beam selected by the UE based on the received beam index.

  In step 204, the base station determines whether or not the determined beam is a K-th level beam, and if the determined beam is not a K-th level beam, the base station executes step 205 and determines If the beam is a Kth level beam, step 206 is executed.

  In step 205, the base station transmits each beam of the next level beam corresponding to the determined beam to the UE and returns to step 202.

  In this step, the method for the base station to transmit each beam of the next level beam corresponding to the determined beam to the UE may be referred to step 201 described above, and thus description thereof is omitted here.

  In step 206, the base station makes the determined beam the beam finally selected by the UE.

  According to the above hierarchical beam selection method, it is not necessary to cause the UE to transmit and measure candidate beams one by one, and the overhead of the beam selection process can be greatly reduced when there are many candidate beams.

FIG. 3 shows a process of performing beam selection between a base station and a single UE when there is only one UE. As shown in FIG. 3, the base station first transmits the reference signals of the _two beams B ₁ and B ₂ at the first level shown in FIG. 1 at the resource position indicated by the filled portion in downlink subframe # 0. . When the UE detects these two beams, the UE selects a beam B ₂ having relatively good performance by measurement, and feeds back the beam index of the selected beam, that is, BI = 2, in the uplink subframe # 5. Next, the base station transmits reference signals of the two beams B ₂₁ and B ₂₂ of the second level beam corresponding to the beam B ₂ shown in FIG. 1 at the resource position indicated by the filled portion in the downlink subframe # 6. To do. When the UE detects these two beams, the UE selects a beam B ₂₂ having relatively good performance by measurement, and feeds back the beam index of the selected beam, that is, BI = 22 in the uplink subframe # 10. Finally, the base station transmits the reference signals of the two beams B ₂₂₁ and B ₂₂₂ of the third level beam corresponding to the beam B ₂₂ shown in FIG. 1 at the resource position indicated by the filled portion in the downlink subframe # 11. Send. When the UE detects these two beams, the UE selects a beam B ₂₂₂ having relatively good performance by measurement, and feeds back the beam index of the selected beam, that is, BI = 223, in uplink subframe # 15. In response to the instruction of the feedback mode instruction bit, information such as the current CQI, RI, and PMI is also fed back. Thus far, the beam selection process is completed. As can be seen from this, after three selection processes, a total of 6 beams are transmitted from the base station, and the UE can accurately select the beam most suitable for itself from the 8 candidate beams. .

FIG. 4 illustrates a process of performing beam selection between a base station and a plurality of UEs when there are a plurality of UEs. In this example, first, the number of candidate beams is 512, and the number of beam selection levels is 3, that is, each level has 8 beams, and each level beam becomes the next level of 8 beams. Correspond. There are 10 UEs covered by the base station, including UE1, UE2,. In this case, as shown in FIG. 4, the base station first transmits reference signals of _eight beams B ₁ to B ₈ of the first level. When each UE detects these eight beams, each UE selects a beam having relatively good performance by measurement. The UE1 and UE2, select beam _{B 1,} and fed back to BI corresponding, the UE3, select the beam _{B 2,} and feeds back the BI corresponding, UE4 and UE5 selects beam _{B 3,} the corresponding feeding back the BI, UE 6, UE 7, and UE8 selects the beam _{B 5,} and feeds back the BI corresponding, the UE 9, selects the beam _{B 6,} by feeding back the BI corresponding, UE 10 is beam _{B 7} And the corresponding BI was fed back. Next, the base station performs the beam B _{11 to} B ₁₈ , B _{21 to} B ₂₈ , B _{31 to} B ₃₈ , B _{51 to} B ₅₈ , B _{61 to} B ₆₈ , and B _{71 to} B ₇₈ as shown in FIG. Each reference signal is transmitted. When each UE detects these beams, each UE selects a beam having relatively good performance by measurement. UE1 selects the beam _{B 11,} and feeds back the BI corresponding, UE2 selects the beam _{B 15,} and feeds back the BI corresponding, UE3 selects the beam _{B 25,} and feeds back the BI corresponding , UE4 selects the beam _{B 32,} and feeds back the BI corresponding, UE 5 selects the beam _{B 36,} and feeds back the BI corresponding, UE 6, UE 7, and UE8 selects the beam _{B 54,} The corresponding BI is fed back, the UE 9 selects the beam B ₆₇ and feeds back the corresponding BI, and the UE 10 selects the beam B ₇₂ and feeds back the corresponding BI. Then, according to the beams selected by the UE, the base station transmits third level beam reference signals corresponding to these beams. Finally, each UE selects the beam with the best performance based on the detection result for each beam, and feeds back the beam index of the selected beam and information such as CQI, RI, and PMI to the base station. . As shown in FIG. 4, in this example, in the three beam transmission processes from the first level to the third level, the number of beams transmitted from the base station to the UE is 8 + 6 × 8 + 8 × 8 = 120 in total. The number of candidate beams is 512. Therefore, according to such a hierarchical beam selection method, the number of beams to be transmitted from the base station can be greatly reduced, and the overhead of the beam selection process can be greatly reduced.

  In addition, as described above, in the 5G era, by combining large-scale MIMO technology and beamforming technology, more antennas and more beams can be obtained, and the beam width is also increased. Since it becomes narrower, a more accurate directional service can be realized. However, as the width of the beam becomes narrower, the influence of the beam on the phase noise increases, which affects the accuracy of beam selection and the communication quality. Therefore, among the multi-level beams of the method of the present application, the upper level beam can cover the corresponding lower level beam, that is, the width of the upper level beam is larger than the width of the lower level beam. Therefore, the UE first selects from a wide beam and then selects from a narrow beam. Thereby, it is possible to better resist the influence of the phase noise on the accuracy of beam selection, improve the accuracy of beam selection, and further guarantee the communication quality.

  In addition, the present application provides other beam selection methods to further resist the effects of phase noise on the accuracy of beam selection. In this method, after the candidate beam finally selected by the UE is determined, phase adjustment is further performed on the candidate beam finally selected by the UE, and the adjusted beam is transmitted to the UE. The UE performs beam detection on the beam after phase adjustment, and then feeds back the beam index of the selected beam to the base station. At this time, the base station can determine the phase-adjusted candidate beam selected by the UE. In this method, by performing phase adjustment on the candidate beam selected by the UE, the beam can be accurately directed to the UE, and the influence of the phase noise on the accuracy of beam selection and communication quality can be avoided. .

  FIG. 5 shows a beam selection method in the embodiment of the present application. As shown in FIG. 5, the method includes the following steps.

  In step 501, the base station transmits each first level beam to the UE.

  In step 502, the UE performs beam detection, searches for a beam having the best reception performance from among them, sets the selected beam, and feeds back the beam index (BI) of the selected beam to the base station.

  In step 503, the base station receives the beam index fed back from the UE and determines a beam corresponding to the received beam index.

  In step 504, the base station determines whether or not the determined beam is a Kth level beam, and if the determined beam is not a Kth level beam, the base station executes step 505 and determines If the beam is a K-th level beam, step 506 is executed.

  In step 505, the base station transmits each beam of the next level beam corresponding to the determined beam to the UE and returns to step 502.

  Since the implementation method of steps 501 to 505 may be the same as the implementation method of steps 201 to 205, description thereof is omitted here.

  In step 506, the base station rotates the beam selected by the UE s times around the beam selected by the UE in a clockwise direction and a counterclockwise direction, respectively, with a preset rotation accuracy. In total, 2s beams are obtained. Of these, the angular difference between every two adjacent beams is one rotational accuracy. Here, s is a natural number.

  In this embodiment, the rotation accuracy and the number of rotations s are set according to the width of the candidate beam and the angle between adjacent candidate beams, and among these 2s + 1 beams, the beam adjacent to each beam is a small angle. It may be determined to shift and ensure that it is not close to other candidate beams after the shift.

  In step 507, the base station transmits the obtained 2s beams together with the beam selected by the UE to the UE.

  In this step, the base station transmits a BRS of 2s + 1 beams in total to the UE.

  In step 508, the UE performs beam detection, searches for a beam having the best reception performance from among them, sets the selected beam, and feeds back the beam index (BI) of the selected beam to the base station.

  In step 509, the base station receives the beam index fed back from the UE and determines a beam corresponding to the received beam index.

  In step 510, the base station makes the determined beam the beam finally selected by the UE.

  According to the above steps 506 to 510, fine adjustment of the phase of the selected beam is realized, and the selected beam can be directed to the UE more precisely, and the accuracy and communication quality of beam selection due to phase noise can be achieved. Is effectively avoided.

FIG. 6 shows an example in which fine phase adjustment is performed on the selected beam. In the example shown in FIG. 6, s = 2. In this example, the base station first rotates the candidate beam B ₂₁₂ selected by the UE twice in the counterclockwise direction and the clockwise direction by one rotation accuracy, respectively, to thereby generate four beams B _{212. -2} , B _212-1 , and B _{212 + 1} , B _{212 + 2} . In this case, the base station _{transmits BRSs of} five beams B _212-2 , B _212-1 , B ₂₁₂ , B _{212 + 1} , and B _{212 + 2} to the UE. After performing beam detection, the UE selected B _{212 + 1} and fed back. In this case, the base station can determine that beam B _{212 + 1} can be more accurately directed at the UE.

  As an alternative to the above step 510, after the execution of step 509 is completed, the base station may further execute the following procedure as shown in FIG.

  In step 510A, it is determined whether or not the beam determined this time is the endmost beam obtained by rotation, and the beam determined this time is the endmost beam obtained by rotation. If there is, step 510B is executed, and if the beam determined this time is not the endmost beam obtained by rotation, step 510C is executed.

  In step 510B, the base station makes the determined beam the beam finally selected by the UE.

  In step 510C, the base station subsequently rotates the beam further s times around the beam selected by the UE in the clockwise direction and the counterclockwise direction by a preset rotation accuracy. , A total of 2s beams are obtained. Of these, the angular difference between every two adjacent beams is one rotational accuracy. Here, s is a natural number.

  In step 510D, the base station transmits the obtained 2s beams together with the beam selected by the UE to the UE, and returns to step 508.

  According to the above steps 506 to 509 and 510A to 510D, fine adjustment of the phase of the selected beam is realized, the selected beam can be directed to the UE more precisely, and the accuracy of beam selection due to phase noise can be improved. And the effect on communication quality is effectively avoided.

8a and 8b show an example in which fine phase adjustment is performed on the selected beam. In the example shown in FIGS. 8a and 8b, s = 1. In this example, the base station first rotates the candidate beam B ₁₂₁ selected by the UE in the counterclockwise direction and the clockwise direction by one rotation accuracy, respectively, to thereby obtain two beams B _121-1 and B _{121 + 1} is obtained. In this case, as shown in FIG. 8a, the base station transmits three beams B _121-1 , B ₁₂₁ , and B _{121 + 1} to the UE. After performing the beam detection, the UE selected B _{121 + 1} and fed back. In this case, the base station subsequently rotates the beam B _{121 + 1} around the beam B _{121 + 1} in the counterclockwise direction and the clockwise direction by one rotation accuracy to obtain _two beams B ₁₂₁ and B _{121 + 2} . In this case, as shown in FIG. 8b, the base station transmits three beams B ₁₂₁ , B _{121 + 1} , and B _{121 + 2} to the UE. At this time, if through the beam detection, if the UE selects the beam _{B 121 + 1,} beam _{B 121 + 1} is ultimately selected beam by the UE. If the UE selects beam B _{121 + 2} , the base station further rotates counterclockwise and clockwise around beam B _{121 + 2} to obtain a new beam, which is then transmitted to the UE for selection And repeat until the final beam is found by the UE.

  Corresponding to the beam selection method, in the embodiment of the present application, a base station for realizing the beam selection method is also provided. FIG. 9 shows the internal configuration of the base station in the embodiment of the present application. As shown in FIG. 9, the base station performs beam selection setting, and satisfies the above-described requirements, and sets the correspondence between each level of the beam from the first level to the Kth level and the beam of each level. A setting module 901 for determining, a beam reference signal transmitting module 902 for transmitting a beam reference signal to the UE, a feedback receiving module 903 for receiving a beam index fed back from the UE, and a first level set by the setting module 901 The beam reference signal transmission module 902 is controlled to transmit the beam reference signal of the beam to the UE, and the beam index fed back from the UE is received by the feedback receiving module 903, and then corresponds to the beam index fed back from the UE. Determine the beam , Determine whether the beam is a K-th level beam, and if the beam is a K-th level beam, the beam is a beam finally selected by the UE, and the beam is A control module 904 that controls the beam reference signal transmission module 902 to transmit the beam reference signal of the next level beam corresponding to the beam to the UE if it is not a K level beam.

  The base station performs phase adjustment on the beam selected by the UE, controls the beam reference signal transmission module 902 to transmit the beam reference signal of the beam after phase adjustment to the UE, and is fed back from the UE. After the beam index is received by the feedback reception module 903, a phase adjustment module 905 may be further included that determines a beam corresponding to the beam index fed back from the UE to be a beam finally selected by the UE.

  The phase adjustment module 905 may perform phase adjustment by the method of steps 506 to 510 or the methods of steps 506 to 509 and 510A to 510D.

  As described above, the base station that realizes the beam selection described above can significantly reduce the signaling overhead of the beam selection process by the hierarchical beam selection method. Also, since the upper level beam width to be set is wider than the lower level beam width, this configuration can effectively resist the influence of phase noise on the accuracy of beam selection and communication quality, ie, the beam The accuracy of selection can be improved and the communication quality of the system can be further improved.

  In addition, the block diagram used for description of the said embodiment has shown the block of the functional unit. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device physically and / or logically coupled, and two or more devices physically and / or logically separated may be directly and / or indirectly. (For example, wired and / or wirelessly) and may be realized by a plurality of these devices.

  FIG. 10 is a schematic diagram of another configuration of the base station in the embodiment of the present application. As shown in FIG. 10, the base station is configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

  Each function in the base station 1000 is obtained by reading predetermined software (program) on hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs computation and controls communication by the communication device 1004, or the memory 1002 Further, it may be realized by controlling data reading and / or writing in the storage 1003.

  In some embodiments, machine readable instructions are stored in the storage 1003, the machine readable instructions include beams from the first level to the Kth level (K is a natural number) and the correspondence between the beams at each level. , Step b for transmitting each first level beam to a user equipment (UE), step c for receiving a beam index fed back from the UE, and a beam corresponding to the received beam index If the determined beam is not the K-th level beam, each beam of the next level beam corresponding to the determined beam is transmitted to the UE, and the process returns to step c. If it is a K-level beam, the step d is made to make the determined beam the candidate beam selected by the UE. Is executable by the processor 1001.

  In the above description, the hardware configuration of the base station 1000 may be configured to include one or a plurality of members illustrated in the figure, or may be configured not to include some members.

  For example, although only one processor 1001 is illustrated, there may be a plurality of processors. Further, the processing may be executed by one processor, or the processing may be executed by one or more processors simultaneously, sequentially, or in another manner. Note that the processor 1001 may be implemented by one or more chips.

  The storage 1003 is a computer-readable recording medium such as a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Programmable EPROM), a RAM (Random Access Memory), or any other suitable storage medium. You may be comprised by one. The storage 1003 may be called a register, a cache, a main memory (main storage device), or the like. The storage 1003 can store programs (program codes), software modules, and the like that can be executed to implement the uplink data transmission method according to the embodiment of the present application. The base station includes a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a FPGA (Filmable Prog). Some or all of the functional blocks may be realized by the hardware. For example, each of the processors 1001 may be implemented by at least one of these hardware.

  Note that the terms described in this specification and / or terms necessary for understanding this specification may be replaced with terms having the same or similar meaning. For example, the channel and / or symbol may be a signal (signaling). The signal may be a message. The reference signal may be abbreviated as RS (Reference Signal), and may be referred to as a pilot, a pilot signal, or the like according to an applied standard.

  In addition, the information, parameters, and the like described in this specification may be expressed as absolute values, relative values from predetermined values, or may be expressed as other corresponding information. . For example, the radio resource may be indicated by a predetermined index. Further, the mathematical formulas that use these parameters may differ from those explicitly disclosed herein.

  Information, signals, etc. described herein may be represented using any of a variety of different technologies. For example, data, commands, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these May be represented by a combination of

  Also, information, signals, etc. can be output from the upper layer to the lower layer and / or from the lower layer to the upper layer. Information, signals, and the like may be input / output via a plurality of network nodes.

  Input / output information, signals, and the like may be stored in a specific location (for example, a memory) or managed by a management table. Input / output information, signals, and the like can be overwritten, updated, or added. The output information, signals, etc. may be deleted. Input information, signals, and the like may be transmitted to other devices.

  The notification of information is not limited to the aspect / embodiment described in the present specification, and may be performed by other methods. For example, information notification may be physical layer signaling (for example, downlink control information (DCI), uplink control information (UCI)), higher layer signaling (for example, RRC (Radio Resource Control) signaling, It may be implemented by broadcast information (master information block (MIB: Master Information Block), system information block (SIB: System Information Block), etc.), MAC (Medium Access Control) signaling), other signals, or a combination thereof.

  The physical layer signaling may be referred to as L1 / L2 (Layer 1 / Layer 2) control information (L1 / L2 control signal), L1 control information (L1 control signal), or the like. The RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, or the like. The MAC signaling may be notified by, for example, a MAC control element (MAC CE (Control Element)).

  In addition, notification of predetermined information (for example, notification of “being X”) is not limited to explicitly performed, but implicitly (for example, by not performing notification of the predetermined information or another (By notification of information).

  The determination may be performed by a value represented by 1 bit (0 or 1), or may be performed by a boolean value represented by true or false. It may be performed by comparing numerical values (for example, comparing with a predetermined value).

  Software, whether it is called software, firmware, middleware, microcode, hardware description language, or other names, instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc. should be interpreted broadly.

  Further, software, instructions, information, and the like may be transmitted / received via a transmission medium. For example, software may use websites, servers using wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and / or wireless technology (infrared, microwave, etc.) , Or other remote sources, these wired and / or wireless technologies are included within the definition of transmission media.

  As used herein, the terms “system” and “network” are used interchangeably.

  In this specification, “BS (Base Station)”, “wireless base station”, “eNB”, “gNB”, “cell”, “sector”, “cell group”, “carrier” and “component carrier” Can be used interchangeably. A base station may also be referred to in terms such as a fixed station, a NodeB, an eNodeB (eNB), an access point, a transmission point, a reception point, a femto cell, and a small cell.

  A base station can accommodate one or more (eg, three) cells (also referred to as sectors). When a base station accommodates multiple cells, the entire coverage area of the base station can be partitioned into multiple smaller areas, each smaller area being divided into a base station subsystem (e.g., an indoor small base station (RRH: The term “cell” or “sector” refers to a part or all of the coverage area of a base station and / or base station subsystem that provides communication service in this coverage. Point to.

  In this specification, the terms “mobile station (MS)”, “user terminal”, “user equipment (UE)” and “terminal” may be used interchangeably. A base station may also be referred to in terms such as a fixed station, a NodeB, an eNodeB (eNB), an access point, a transmission point, a reception point, a femto cell, and a small cell.

  A mobile station is defined by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless It may also be called terminal, remote terminal, handset, user agent, mobile client, client or some other suitable terminology.

  In addition, the radio base station in this specification may be read as a user terminal. For example, each aspect / embodiment of the present invention may be applied to a configuration in which communication between a radio base station and a user terminal is replaced with communication between a plurality of user terminals (D2D: Device-to-Device). In this case, it is good also as a structure which UE700 has the function which the above-mentioned eNB has. In addition, words such as “up” and “down” may be read as “side”. For example, the uplink channel may be read as a side channel.

  Similarly, the user terminal in this specification may be read by a radio base station. In this case, it is good also as a structure which a user terminal has the function which the above-mentioned base station has.

  In this specification, the specific operation performed by the base station may be performed by the upper node in some cases. In a network composed of one or more network nodes having a base station, various operations performed for communication with a terminal are performed by the base station and one or more network nodes other than the base station (for example, It is obvious that the operation can be performed by MME (Mobility Management Entity), S-GW (Serving-Gateway) and the like, or a combination thereof.

  Each aspect / embodiment described in this specification may be used independently, may be used in combination, or may be switched in accordance with execution. Further, the processing procedures, sequences, flowcharts, and the like of each aspect / embodiment described in the present specification may be switched in order as long as there is no contradiction. For example, the methods described herein present the elements of the various steps in an exemplary order and are not limited to the specific order presented.

  Each aspect / embodiment described in this specification is based on LTE (Long Term Evolution), LTE-A (LTE-Advanced), LTE-B (LTE-Beyond), SUPER 3G, IMT-Advanced, 4G (4th generation mobile). (communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), New-RAT (Radio Access Technology), NR (New Radio Access Technology), NR (New Radio Access Technology). GSM (registered trademark) (Glob l System for Mobile communications (CDMA), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.2U -Wideband), Bluetooth (registered trademark), other appropriate wireless communication methods, and / or the next generation system extended based on these may be applied.

  As used herein, the phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on.”

  As used herein, the term “determining” may encompass a wide variety of actions. For example, “determination (decision)” includes calculation, calculation, processing, deriving, investigating, searching up (eg, table, database or other data). (Search by structure), confirmation, etc. may be regarded as “determination (determination)”. In addition, “determination (decision)” includes receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access (output). “accessing” (for example, accessing data in the memory) may be regarded as “determination (determination)”. In addition, “determination (determination)” may be regarded as “determination (determination)” such as resolving, selection, selecting, establishing, comparing, and the like. That is, “determination (determination)” may be regarded as “determination (determination)” of some operation.

  As used herein, the terms “connected”, “coupled”, or any variation thereof, refers to any direct or indirect connection between two or more elements or By coupling, it can include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” to each other. The coupling or connection between the elements may be physical, logical, or a combination thereof. For example, “connection” may be read as “access”. As used herein, the two elements are radio frequency by using one or more wires, cables and / or printed electrical connections, and as some non-limiting and non-inclusive examples It can be considered to be “connected” or “coupled” to each other, such as by using electromagnetic energy having wavelengths in the region, microwave region, and / or light (both visible and invisible) region.

  Where the term “including”, “comprising”, and variations thereof are used herein or in the claims, these terms are inclusive, as are the terms “comprising”. Intended to be Further, the term “or” as used herein or in the claims is not intended to be an exclusive OR.

  The above is only an example of the present application, and does not limit the protection scope of the present application. Various modifications, equivalent replacements, improvements and the like made within the spirit and principle of the present application should all be included in the protection scope of the present application.

901 Setting module 902 Beam reference signal transmission module 903 Feedback reception module 904 Control module 905 Phase adjustment module 1000 Base station 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

FIG. 3 shows a process of performing beam selection between a base station and a single UE when there is only one UE. As shown in FIG. 3, the base station first transmits the reference signals of the two beams B1 and B2 at the first level shown in FIG. 1 at the resource position indicated by the filled portion in downlink subframe # 0. When the UE detects the two beams, the UE selects a beam B2 having relatively good performance by measurement, and feeds back the beam index of the selected beam, that is, BI = 2 in the uplink subframe # 5. Next, the base station transmits the reference signals of the two beams B21 and B22 of the second level beam corresponding to the beam B2 illustrated in FIG. 1 at the resource position indicated by the filled portion in the downlink subframe # 6. When the UE detects these two beams, the UE selects a beam B22 having relatively good performance by measurement, and feeds back the beam index of the selected beam, that is, BI = 22 in the uplink subframe # 10. Finally, the base station transmits the reference signals of the two beams B221 and B222 of the third level beam corresponding to the beam B22 shown in FIG. 1 at the resource position indicated by the filled portion in the downlink subframe # 11. The UE detects the two beams, by measurement, performance select relatively good beam B 222, in the uplink subframe # 15, the beam index of the selected beam, i.e., with feeding back the BI = 22 2 In response to the instruction of the feedback mode instruction bit, information such as the current CQI, RI, and PMI is also fed back. Thus far, the beam selection process is completed. As can be seen from this, after three selection processes, a total of 6 beams are transmitted from the base station, and the UE can accurately select the beam most suitable for itself from the 8 candidate beams. .

FIG. 4 illustrates a process of performing beam selection between a base station and a plurality of UEs when there are a plurality of UEs. In this example, first, the number of candidate beams is 512, the number of beam selection levels is 3, that is, there are 8 beams at the first level, and each of the beams at each level has 8 of the next level. Corresponds to one beam. There are 10 UEs covered by the base station, including UE1, UE2,. In this case, as shown in FIG. 4, the base station first transmits reference signals of _eight beams B ₁ to B ₈ of the first level. When each UE detects these eight beams, each UE selects a beam having relatively good performance by measurement. The UE1 and UE2, select beam _{B 1,} and fed back to BI corresponding, the UE3, select the beam _{B 2,} and feeds back the BI corresponding, UE4 and UE5 selects beam _{B 3,} the corresponding feeding back the BI, UE 6, UE 7, and UE8 selects the beam _{B 5,} and feeds back the BI corresponding, the UE 9, selects the beam _{B 6,} by feeding back the BI corresponding, UE 10 is beam _{B 7} And the corresponding BI was fed back. Next, the base station performs the beam B _{11 to} B ₁₈ , B _{21 to} B ₂₈ , B _{31 to} B ₃₈ , B _{51 to} B ₅₈ , B _{61 to} B ₆₈ , and B _{71 to} B ₇₈ as shown in FIG. Each reference signal is transmitted. When each UE detects these beams, each UE selects a beam having relatively good performance by measurement. UE1 selects the beam _{B 11,} and feeds back the BI corresponding, UE2 selects the beam _{B 15,} and feeds back the BI corresponding, UE3 selects the beam _{B 25,} and feeds back the BI corresponding , UE4 selects the beam _{B 32,} and feeds back the BI corresponding, UE 5 selects the beam _{B 36,} and feeds back the BI corresponding, UE 6, UE 7, and UE8 selects the beam _{B 54,} The corresponding BI is fed back, the UE 9 selects the beam B ₆₇ and feeds back the corresponding BI, and the UE 10 selects the beam B ₇₂ and feeds back the corresponding BI. Then, according to the beams selected by the UE, the base station transmits third level beam reference signals corresponding to these beams. Finally, each UE selects the beam with the best performance based on the detection result for each beam, and feeds back the beam index of the selected beam and information such as CQI, RI, and PMI to the base station. . As shown in FIG. 4, in this example, in the three beam transmission processes from the first level to the third level, the number of beams transmitted from the base station to the UE is 8 + 6 × 8 + 8 × 8 = 120 in total. The number of candidate beams is 512. Therefore, according to such a hierarchical beam selection method, the number of beams to be transmitted from the base station can be greatly reduced, and the overhead of the beam selection process can be greatly reduced.

In step 510A, it is determined whether or not the beam determined this time is the endmost beam obtained by rotation, and the beam determined this time is the endmost beam obtained by rotation. some cases, perform the steps 510 C, this time determined beam, if not the beam endmost obtained by rotating, executes step 510 B.

The storage 1003 is a computer-readable recording medium. For example, the storage 1003 is at least a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Programmable EPROM), a RAM (Random Access Memory), or any other suitable storage medium. You may be comprised by one. The storage 1003 may be called a register, a cache, a main memory (main storage device), or the like. The storage 1003 can store a program (program code), a software module, and the like that can be executed to perform the beam selection method according to the embodiment of the present application. In addition, the base station includes a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD) hardware, and a FPGA (Filmable Progable Hardware). Some or all of the functional blocks may be realized by the hardware. For example, each of the processors 1001 may be implemented by at least one of these hardware.

In addition, the radio base station in this specification may be read as a user terminal. For example, each aspect / embodiment of the present invention may be applied to a configuration in which communication between a radio base station and a user terminal is replaced with communication between a plurality of user terminals (D2D: Device-to-Device). In this case, it is also a function of the eNB described above configured to have the U E. In addition, words such as “up” and “down” may be read as “side”. For example, the uplink channel may be read as a side channel.

Similarly, the user terminal in this specification may be read by a radio base station. In this case, it is good also as a structure which a base station has the function which the above-mentioned user terminal has.

Claims (17)

A beam selection method,
A step a for presetting the beam from the first level to the Kth level (K is a natural number) and the correspondence between the beams at each level;
Transmitting each first level beam to a user equipment (UE); b.
Receiving a beam index fed back from the UE; c.
Determining a beam corresponding to the received beam index and, if the determined beam is not a K-th level beam, transmitting each beam of the next level beam corresponding to the determined beam to the UE; step c Returning to step d, if the determined beam is a Kth level beam, make the determined beam a candidate beam selected by the UE;
A method comprising: The method of claim 1, wherein the first to K level beams satisfy the following condition.
Each beam at the i-th level corresponds to two or more beams at the (i + 1) -th level,
Any of the i + 1 level beams corresponds to one beam of the i level,
The Kth level beam includes N (N is a natural number) candidate beams,
The direction of each beam at the i-th level correlates to the direction of two or more beams at the (i + 1) -th level corresponding to the beam,
i = [1, K-1].   3. The method according to claim 1, wherein the width of the i-th level beam is larger than the width of the i + 1-th level beam, and i = [1, K-1]. The direction of each beam at the i-th level correlates with the direction of two or more beams at the (i + 1) -th level corresponding to the beam,
The correlation coefficient between the coefficient of the i-th level beam and the coefficient of the i + 1-th level beam corresponding to the beam is greater than a preset threshold value.
The method according to claim 2.   5. The method of claim 4, wherein the beam coefficients include a beam array factor. Transmitting each beam of the first level to a user equipment (UE),
Configure the beam reference signal (BRS) resource by radio resource control (RRC) signaling or dynamic control signaling,
Transmitting BRS of each beam at the first level in the configured BRS resource,
The method according to claim 1. Transmitting each beam of the first level to a user equipment (UE),
In radio resource control (RRC) signaling, beam reference signal (BRS) resources are set in advance,
When preparing to transmit BRS, notify the UE to prepare to receive BRS by dynamic signaling,
Transmitting BRS of each beam at the first level in the configured BRS resource,
The method according to claim 1. Sending each beam of the next level beam corresponding to the determined beam to the UE,
Configure the beam reference signal (BRS) resource by radio resource control (RRC) signaling or dynamic control signaling,
Transmitting the BRS of each beam at the next level in the configured BRS resource,
The method according to claim 1. Sending each beam of the next level beam corresponding to the determined beam to the UE,
In radio resource control (RRC) signaling, beam reference signal (BRS) resources are set in advance,
When preparing to transmit BRS, notify the UE to prepare to receive BRS by dynamic signaling,
Transmitting the BRS of each beam at the next level in the configured BRS resource,
The method according to claim 1. Informing the UE to prepare to receive BRS by the dynamic signaling,
When a BRS instruction bit is added to downlink control information (DCI) related to downlink transmission transmitted on the downlink control channel and the BRS instruction bit is 1, it is indicated that the base station starts transmission of BRS,
Setting the BRS indication bit to 1 when preparing to transmit BRS,
10. A method according to claim 7 or claim 9, wherein Further comprising notifying the UE of the beam index feedback mode;
The beam index feedback mode includes a mode in which no feedback is required, a mode in which only the beam index of the selected beam is fed back, a channel quality indicator (CQI), a rank indicator in addition to the beam index of the selected beam. Mode in which feedback (RI) and precoding matrix indicator (PMI) also need to be fed back;
The method of claim 1, comprising: Informing the UE of the feedback mode of the beam index is
Adding a feedback mode indication bit to the DCI for downlink transmission transmitted on the downlink control channel;
When the feedback mode indication bit is 0, it indicates that it is not necessary to feed back, and when the feedback mode indication bit is 1, it indicates that only the beam index of the selected beam needs to be fed back. If the feedback mode indication bit is 2, it indicates that not only the beam index of the selected beam needs to be fed back, but also the current CQI, RI, and PMI need to be fed back.
The method according to claim 11. Making the determined beam a candidate beam selected by the UE,
Phase adjustment is performed on the determined beam, a beam reference signal of the beam after phase adjustment is transmitted to the UE,
Receiving the beam index fed back from the UE;
Determining a beam corresponding to the beam index fed back from the UE to be a beam selected by the UE,
The method according to claim 1. Performing phase adjustment on the determined beam comprises
The determined beam is rotated s times (where s is a natural number) by a predetermined rotation accuracy in the clockwise direction and the counterclockwise direction around the determined beam, for a total of 2s. Obtaining a beam, of which the angular difference between every two adjacent beams is one rotational accuracy,
The method according to claim 13. A base station,
A processor;
And a storage connected to the processor,
The storage stores a machine readable command module executable by the processor,
The machine readable command module comprises:
A setting module for performing beam selection setting and determining a beam of each level from the first level to the Kth level (K is a natural number) and a correspondence relationship between the beams of each level;
A beam reference signal transmission module for transmitting a beam reference signal to a user equipment (UE);
A feedback receiving module for receiving a beam index fed back from the UE;
After the beam reference signal transmission module is controlled to transmit the beam reference signal of the first level beam set by the setting module to the UE, and the beam index fed back from the UE is received by the feedback receiving module, from the UE Determine a beam corresponding to the fed-back beam index, determine whether the beam is a Kth level beam, and if the beam is a Kth level beam, the beam is selected by the UE A control module that controls the beam reference signal transmission module to transmit a beam reference signal of the next level beam corresponding to the beam to the UE if the beam is not a Kth level beam; including,
A base station characterized by that. Phase adjustment is performed on the beam selected by the UE, the beam reference signal transmission module is controlled to transmit the beam reference signal of the beam after phase adjustment, and the beam index fed back from the UE is received by the feedback reception module. And a phase adjustment module for determining a beam corresponding to the beam index fed back from the UE to be a beam selected by the UE,
The base station according to claim 15. A non-volatile computer-readable storage medium,
Machine-readable instructions are stored in the storage medium, and the machine-readable instructions are:
A step a for presetting the beam from the first level to the Kth level (K is a natural number) and the correspondence between the beams at each level;
Transmitting each first level beam to a user equipment (UE); b.
Receiving a beam index fed back from the UE; c.
Determining a beam corresponding to the received beam index and, if the determined beam is not a K-th level beam, transmitting each beam of the next level beam corresponding to the determined beam to the UE; step c Returning to step d, if the determined beam is a Kth level beam, make the determined beam a candidate beam selected by the UE;
A non-volatile computer readable storage medium characterized in that it can be executed by a processor to complete